R-f coupling arrangements for traveling wave tubes



y 1959 J. H. BRYANT HAL 2,894,227

R-F COUPLING ARRANGEMENTS FOR TRAVELING WAVE TUBES Filed Aug. 21, 1952 2She ets-Sheet 1 VIII An/f ENW July 7, 1959 J. H. BRYANT ETAL 2,894,227

R-F COUPLING ARRANGEMENTS FOR TRAVELING WAVE TUBES Filed Aug. 21, 1952 2Sheets-Sheet 2 129. 5 T4 mm I IIIIIIIII/l/I/ lIllIl/llIlIIlllIII/lll.

.g/ pw J INVENTORS 1 41 JOHN H- BRYANT ALBERT "1- PE/FER 50 BY 7297 w.W/LMAKTl-l ATTORNEY R-F' COUPLING ARRANGEMENTS FOR TRAVELING wAvE TUBESJolmH. Bryant and Albert G. Peifer, Nutley, and Robert W. Wilmarth,Rutherford, N.J., assignors to international Telephone and TelegraphCorporation, a corporation of Maryland Application August 21, 1952,Serial No. 305,538

14 Claims. (Cl. 33397) This invention relates to traveling wave electrondischarge devices and more particularly to R-F coupling arrangementstherefor.

The traveling wave type of tube is particularly useful in wide bandmicrowave systems since it is capable of amplifying radio frequencyenergy over a very wide band of frequencies. The tube includes a form oftransmission line, usually a helix, for transmission of microwave energyfor interaction with an electron beam closely associated with the line.The helical characteristic of the transmission line is such that theaxial velocity of microwave signals conducted along the helical path isapproximately the same as or slightly slower than the velocity of theelectrons of the beam, whereby the electric field of the microwavesignals interacts with the electron beam for amplification of themicrowave signals. In the copending application of J. H. Bryant and T.J.

Marchese, Serial No. 221,862, filed April 19, 1951, a compact travelingwave tube is provided characterized in that two coaxial terminals forthe radio frequency input and output connections are brought out at oneend.

It is one of the objects of the present invention to provide an R-Fcoupling arrangement for a traveling wave tube having its R-Fconnections at one end, suitable for connection to either coaxial linesor waveguides.

It is a further object of this invention to provide a traveling wavetube which is interchangeably adapted for use with either coaxial lineor waveguide transmission systems.

A feature of this invention is the rigid R-F end structural arrangementof a traveling wave tube having the output and input R-F connectionslocated at the same end. The end plate of such a traveling wave tube ismade in two parts, an inner disc through which R-F output and inputcoaxial terminals are disposed and an annular ring portion receivablymounted on the envelope of the tube. An adapter is provided to couplesaid coaxial terminals to input and output line probes coupled to asection of Waveguide. A second adapter is provided which may be utilizedin place of the first adapter for coupling said R-F terminals to coaxiallines through usual R-F circuit fittings. Through the use of either oneof the two adapters with a single traveling wave tube, the tube may beadapted for insertion in either a coaxial line or waveguide transmissionsystem.

The above-mentioned and other features and objects of this inventionwill become more apparent by reference to the following descriptiontaken in conjunction with the accompanying drawings, in which:

Fig. l is an 'explodedsectional view of the R-F end of a traveling wavetube and adapter for connection to 'a'coa'xial line transmission system;

Fig. 2 is a cross-sectional view taken along lines 2-2 of Fig. l;

Fig. 3 is an exploded sectional view of the R-F end of a traveling wavetube and adapter for connection to a waveguide transmission system; and

atent 2,894,227 Patented July 7, 1959 ice Fig. 4 is a cross-sectionalview taken along lines 44 of Fig. 3.

Referring to Figs. 1 and 2 of the drawing, the traveling wave tube andadapter for coupling to an R-F coaxial line transmission system is shownto comprise a traveling wave tube 1 having a cylindrical housing 2containing in one end thereof a radio frequency transmission linecoupling unit 3, and in the opposite end thereof an electron gun unit(not shown). The housing has mounted thereon a magnetic unit 4, shown tobe an electromagnetic coil, although a permanent magnet may be used. TheR-F transmisison line coupling unit 3 comprises a barrier plate 5through which are mounted input R-F line connection 6 to the helix 7,output R-F line connection 8 to helix 7, and an electron collectorterminal 9. The input connection 6 comprises a coaxial line having anouter conductor 10 and an inner conductor 11, the connections beingclosed by insulator 12 sealed between the outer and inner conductors 10and 11. The output connection 8 likewise comprises a coaxial structurehaving an outer conductor 13 and an inner conductor 14 sealed byinsulation 15. The inner conductors 11 and 14 of the R-F lineconnections 6 and 8 extend beyond the outer conductors 1'0 and 13forming R-F input probe 16 and R-F output probe 17. Mounted on the innerside of barrier plate 5 is a radio frequency transmission linepreferably in the form of a helix 7, although some other configuration,such as a plurality of annular discs or plates, may be used, whereby theaxial velocity of the radio frequency energy is made preferably slightlyslower than the velocity of the beam of electrons projected from theelectron gun unit.

End plate or cup 18 is mounted to the housing 2 by means of its annularrim 19. The input and output R-F line connections 6 and 8 are broughtthrough holes 20 and 21 in the end plate 18. Hollow posts 22 and 23protect the connections 6 and 8 and support the connections in alignmentto be coupled to the adapter. Rigidly secured to end plate 18 aresupporting posts 36 and 37 each having a threaded hole in its outer endto receive a connecting screw.

The adapter for coupling an R-F coaxial transmission system to the R-Fline connections 6 and 8 of traveling wave tube 1 comprises a base plate24 to which is mounted, by means of screws 25 and 26, standard coaxialcoupling units 27 and 28. Each of the coaxial coupling units 27 and 28comprises an outer conductor 29 separated from an inner conductor sleeve30 by insulation 31. R-F coaxial cable is connected to the standardcoupling units 27 and 28 in the usual manner such as by screw threads orstuds. The inner conductors 3%) of coupling units 27 and 28 telescopewith the probes 16 and 17 of R-F line connections 6 and 8. The coaxialcouplers 27 and 28 abut upon and are rigidly secured to the base plate24. In electrical contact with the outer conductors 29 of coaxialcouplers 27 and 28 and supported by base plate 24 are hollow sleeves 33and 34 whose inside diameter is equal to the outside diameter of the R-Fline connections '6 and 8.

In order to couple the traveling wave tube 1 into a coaxial linetransmission system, the sleeves 33 and 34 are fitted over the R-F lineconnections 6 and 8 of the traveling wave tube and screws 35 areinserted through the base plate 24 into the threaded holes of posts 36and 37 which are rigidly attached to end plate 18. When properlyaligned, the outer conductor of the input R-F coaxial transmission lineis coupled through coupling unit 28 and sleeve 34 to the outer conductor10 of the R-F line connection 6 while the inner conductor probe 16 istelescoped into coupling unit 28. The input energy is then coupled tothe helix 7 through a usual R-F transmission line. The outer conductorof the output R-F coaxial transmission line is coupled through couplingunit 27 and sleeve 33 to the outer conductor 13 of the output R-F lineconnection 8 and the inner conductor is coupled through the telescopingof probe 17 and inner conductor 14. The use of sleeves 33 and 34 and theposts 36 and 37 provide a rigid support for the coupling adapter.

Referring to Figs. 3 and 4, an embodiment of an adapter for coupling atraveling wave tube to a waveguide transmission system is shown whereinparts identical with those shown in Figs. 1 and 2 are designated by thesame reference characters. The traveling wave tube 1 has barrier platethrough which input and output R-F line connections 6 and 8 aredisposed. Rigidly coupled to barrier plate 5 by means of nut and bolt 39is the end plate or cup 18 which is held in place by means of itsannular rim 19. R-F line connections 6 and 8 extend through end plate 18secured thereto by means of nut and bolt 39. The electron collectorterminal is not shown in the view of Fig. 2 in order to show nut andbolt 39 coupling the end plate 18 and posts 36 and 37 to barrier plate 5which is not shown in the view of Fig. 1. The coupling adapter for awaveguide transmission system comprises a section of rectangularwaveguide 43 divided into an input and output section by means ofpartition 44. Rigidly secured to the outer surface of waveguide 43 arefour sleeves 45, 46, 47, and 48. Sleeves 45 and 46 fit over R-F lineconnections 6 and 3 in such a manner that probes 16 and 17 extend intowaveguide section 43 a quarter or an odd multiple of a quarterwavelength from partition 44. Sleeves 4-7 and 48 are so located thatthey are received over posts 36 and 37. Sleeves 47 and 48 have aplurality of set screws 49 therethrough which when tightened cause thewaveguide 43 to be rigidly supported by the posts 36 and 37. In use, theadapter has its sleeves 45 and 4-6 slipped over and making contact withthe outer conductors of the input and output R-F connections 6 and 8 ofthe traveling wave tube 1. When these are in position, the input andoutput probes 15 and 17 are so located that they will couple energy awayfrom and into the waveguide section 43. When so located, sleeves 47 and48 will be in place over supporting posts 36 and 37 at which time setscrews 49 may be tightened providing a rigid coupling between the inputand output R-F line connections 6 and 8 of the traveling wave tube Itand the R-F wave-guide termination. Flanges 50 and 51 on the waveguidesection 43 are provided in order to facilitate incorporating waveguidesection 43 into a waveguide transmission system. Braces 52 are providedfor additional mechanical support between the flanges 5t and 51 and therectangular waveguide section.

While we have described above the principles of our invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope or our invention as set forth in the objects thereof and inthe accompanying claims.

We claim:

1. In an electron discharge device having a housing with a pair ofcoaxial radio frequency terminals extending inv parallel relationthrough a wall thereof, each of said terminals including a vacuum sealbetween their inner and outer conductors; a coupling adapter for saidterminals comprising a plate carrying radio frequency transmission linecouplers on one side and a pair of sleeves on the other side thereof,each sleeve being in communication with one of said couplers and meansspaced from. said sleeves and said couplers to removably secure saidplate to said housing wall in a fixed rigid position with said sleeveand said terminals in slidable telescoped relation to thereby protectsaid vacuum seals and said terminals.

2. In an electron discharge device according to claim 1, wherein saidhousing wall has at least one rigid supporting post disposed adjacentsaid terminals and said plate is provided with means for securing theplate to said post.

3. In an electron discharge device according to claim 2, wherein saidpost has a threaded opening therein and said means for securing saidplate to said post includes an element threadably receivable in saidopening.

4. In an electron discharge device according to claim 2, wherein themeans for securing said plate to said post includes a sleeve adapted totelescope over said post and a set screw carried by said sleeve forengagement with said post.

5. In an electron discharge device according to claim 1, wherein thetransmission line couplers comprise a flanged sleeve forming an outerconductor, and a body of dielectric material supported therein having aconductive sleeve axially thereof to form an inner conductor, said innersleeve being adapted to telescope with the inner conductor of one ofsaid terminals when said adapter is applied to said device.

6. In an electron discharge device according to claim 1, wherein each ofsaid couplers comprises a rectangular waveguide with an opening inalignment with an associated one of said sleeves, the inner conductor ofeach terminal being adapted to extend as a probe into the correspondingwaveguide.

7. In an electron discharge device according to claim 1, wherein saidplate comprises a wall of a waveguide section, said waveguide sectionhaving a partition dividing it into two couplers for communication withcorresponding ones of said sleeves.

8. In an electron discharge device according to claim 7, wherein saidmember has at least one post adjacent said terminals and the wall ofsaid waveguide section has a third sleeve adapted to be received oversaid post and means for securing said third sleeve to said post.

9. A coupling adapter for a device having a pair of adjacent paralleldisposed coaxial terminals, each of said terminals including a vacuumseal between their inner and outer conductors, comprising a platecarrying radio frequency transmission line couplers on one side and apair of sleeves on the other side thereof, each said sleeve being incommunication with one of said couplers, said sleeves being adapted toslidably telescope with said terminals and means spaced from saidsleeves and said couplers for removably securing said plate in a fixedrigid position on said device to thereby protect said vacuum seals andsaid terminals.

10. A coupling adapter according to claim 9, wherein the transmissionline couplers comprise a flanged sleeve forming an outer conductor, anda body of dielectric material supported therein having a conductivesleeve axially thereof to form an inner conductor, said inner sleevebeing adapted to telescope with the inner conductor of the terminaltelescoped with the corresponding sleeve of said adapter.

11. A coupling adapter according to claim 9, wherein each of saidcouplers comprises a rectangular waveguide with an opening in alignmentwith an associated one of said sleeves, the inner conductor of eachterminal being adapted to extend as a probe into the correspondingwaveguide.

12. A coupling adapter according to claim 9, wherein said platecomprises a wall of a waveguide section, said waveguide section having apartition dividing it into two couplers for communication withcorresponding ones of said sleeves.

13. A coupling adapter according to claim 12, wherein said device has atleast one rigid supporting post disposed adjacent said terminals andsaid wall of said waveguide section has a third sleeve adapted to betelescoped with said post and means for securing said third sleeve tosaid post.

14. An energy coupling adapter for an electron discharge devicegornprising a housing for said electron.

discharge device having an end wall, a pair of adjacent paralleldisposed coaxial terminals extending through said end wall, each of saidterminals including a vacuum seal between their inner and outerconductors, a plate carrying radio frequency transmission line couplerson one side and a pair of sleeves on the other side thereof, each ofsaid sleeves being in communication with one of said couplers, saidsleeves being adapted to slidably telescope with said terminals, andmeans spaced from said sleeves and said couplers for removably securingsaid plate in a fixed rigid position on said end Wall to thereby protectsaid vacuum seals and said terminals.

References Cited in the file of this patent UNITED STATES PATENTS1,986,269 Jermain Ian. 1, 1935 Potter July 5, 1938 Montgomery Aug. 30,1949 Barnett Aug. 1, 1950 Melcher May 15, 1951 Woodyard July 15, 1952Hines Aug. 26, 1952 Hansell Oct. 21, 1952 Nichols Jan. 6, 1953 GilbertNov. 17, 1953 Sinclair et al. Feb. 28, 1956

